math: two bad edge cases in double_uintptr_t conversion.

This fixes two failing test cases introduced in the
parent commit.

* arith.c (c_dbl_unum): Here, what is wrong that if the
incoming value is a CHR or NUM, we just convert it to a signed
cnum, and return that value. The problem with this is that
negative values are supposed to be out of range for
double_uintptr_t. We now check for negative and route to
the out-of-range error.

* mpi/mpi.c (s_mp_in_big_range): Here, the edge case of
handling the most negative two's complement value is
incorrectly coded. We replace the logic by a simple test for
that exact special case. If a negative bignum being tested
whether it fits into the signed double_intptr_t, then
we check whether its mantissa has the 0x80..00 bit pattern.
That is the only value greater than 0x7F..FF that is
still in range, so we return 1 for that case. We remove the
bogus subtraction (top - neg). After handling the above
special value, we just need to look whether the most
significant word of the bignum is 0x7F...FF or lower.

0 files changed, 0 insertions, 0 deletions